I can't figure out how to position a mannequin at a lower elevation. For instance, if the mannequin is supposed to be sitting on a low chair, or on the floor, or even lying on the floor. The elevation is already 0 and I can't reduce it.
I would tend to say that like in the real world, you should set a posture with knees at a higher position or stretched legs. Or maybe the seats are too low.